This is a long list and with extras I feel should be considered given the OP's request and situation.
After recently going through 3 alternators from AutoZone and NAPA, ending up with the OE from Rock Auto....I'll never buy a reman or new aftermarket again.
If I lived in an area like the OP and/or remote hostile environment, and didn't want to be stranded, my list would on a vehicle with over 90K miles and 7-8 years old, or maybe any vehcle...
Replace:
Alternator, battery, starter, plugs, water pump, hoses and belts, thermostat, idler pulleys O2 sensors, wiper blades, maybe even fuel pump.
What I would keep in the vehicle:
Spare serpentine belt or V-belt
A few feet of various vacuum hoses, heater hose with double end hose barbs for quick repair or bypass, hose clamps.
Spare key/keyfob hidden somewhere
Jumper cables and portable jump start pack
Ignition coil
Case of water, jug of coolant
Headlight bulbs
Spare alternator (pricey part to keep on hand though)
Tire plug kit
12V inflator/high volume hand pump
One set of lugnuts/or just know to remove 1 from each wheel if you lose them during a changeout.
Large pack of zip ties
Very bright flashlight with strobe feature
Head mounted flashlight.
Bungee cords to hold your bumper cover up when you crush an icy snow bank
Recovery strap
Fuses/relays
Solid state relays and these I generally grab from a boneyard for cheap.
Toolkit to replace above parts on side of road including breaker bar, inside and outside torx bits, ratcheting wrenches, picks, side cutters.
Jack stand with a double-thick 3/4" plywood base large enough to cover jack stand feet for uneven or loose surface, also doubles as base for jack.
A bit overkill? Maybe not...but all of those things doesn't take up a whole lot of room. I would carry all of that if I had to travel a long way, in very cold weather and/or long distances over desolate areas.
A large bag of survival gear is another topic.